To discharge several successive portions from a filling machine of the kind mostly used in the preparation of sausages the filling pump must be driven in a pulsating, or stepwise, fashion. It is known to use an oscillating crank-drive therefore which acts on the pump shaft via a free-running drive, the former being secured against any reverse rotation by a ratchet (see DT-OS No. 1,432,513). A second gear train is therefore coupled in parallel with the first gear train inserted between a common drive shaft and the pump shaft which can be selectably inserted by a coupling and which has a greater fixed transmission ratio than the first gear train. Upon insertion of the coupling the pump shaft is driven exclusively by the second gear train through the free-running drive and permits a uniform and continuous discharge of the filling mass in an arbitrarily long strand. The first-described method of operation is primarily applicable if the individual sausage portions are successively filled into a common sausage wrapping and, if necessary, separated from each other by twisting the wrapping between the individual portions. If a crank drive is used, the twisting step is effected during the idle stroke and therefore requires approximately the same time as the filling process. Essentially the same processes occur if portions are only parceled out, i.e if the separation of the individual portions is accomplished by other known separation means.
Mechanically-actuated apportioning pistons change the leverage-ratio of the oscillating drive for the matching thereof to differently sized portions for the filling machine of the aforedescribed type (see DT-PS No. 1,180,151). For a given number of revolutions per minute of the drive motor, the discharge velocity of the mass increases in proportion to the size of the portion to be discharged. It is therefore necessary to change the number of revolutions per minute whenever a relatively large weight adjustment is made, requiring in general a steplessly controlled drive.
Hydraulic filling machines (see DT-PS No. 1,083,094) are, however, also known where the discharge velocity is kept constant due to a uniform supply of hydraulic fluid and where large portions also require larger time intervals. This sytem can only be realized hydraulically. The total effort involved is, however, relatively large.